One sore point seems to remain : Apple HomeKit certification apparently not only applies to the Hue bridge but also to the lamps connected to the Hue Bridge :

Before the 1.11 software update, a bug in the Philips Hue system allowed some non-Apple HomeKit certified lights to work with Apple HomeKit. Our 1.11 software update removed the bug with the result that non-Apple HomeKit certified lights no longer work with Apple HomeKit. This remains the case.

The CC2530 has the 2.4 GHz transmitter and reciever and a microcontroller for the wireless protocol. The Cypress chip handles the buttons and probably the LED’s and speaker (the big square on the right). The UX logic can be in any two of the chips.

The PCB has some capsense buttons that are not on the faceplate. I assume the same PCB is used for both the LivingWhites and LivingColors remotes.